ABSTRACT
All canonical transfer RNAs (tRNAs) have a uridine at position 8, involved in maintaining tRNA tertiary structure. However, the hyperthermophilic archaeon Methanopyrus kandleri harbors 30 (out of 34) tRNA genes with cytidine at position 8. Here, we demonstrate C-to-U editing at this location in the tRNA's tertiary core, and present the crystal structure of a tRNA-specific cytidine deaminase, CDAT8, which has the cytidine deaminase domain linked to a tRNA-binding THUMP domain. CDAT8 is specific for C deamination at position 8, requires only the acceptor stem hairpin for activity, and belongs to a unique family within the "cytidine deaminase-like" superfamily. The presence of this C-to-U editing enzyme guarantees the proper folding and functionality of all M. kandleri tRNAs.
Subject(s)
Cytidine Deaminase/chemistry , Cytidine Deaminase/metabolism , Euryarchaeota/metabolism , RNA Editing , RNA, Archaeal/metabolism , RNA, Transfer/metabolism , Amino Acid Motifs , Catalytic Domain , Crystallography, X-Ray , Deamination , Euryarchaeota/enzymology , Euryarchaeota/genetics , Genes, Archaeal , Models, Chemical , Models, Molecular , Nucleic Acid Conformation , Protein Multimerization , Protein Structure, Tertiary , RNA, Archaeal/chemistry , RNA, Archaeal/genetics , RNA, Transfer/chemistry , RNA, Transfer/geneticsABSTRACT
A previously unknown Leishmania spp., inferred by DNA sequence analysis of the small subunit ribosomal RNA gene and the internal transcribed spacer region (ITS1), was detected in tissue biopsies from patients living in the Eastern Ghanaian community of Taviefe. Restriction fragment length polymorphism analysis of the ITS1 amplicon supports the possibility of an uncharacterized Leishmania spp.
